N.J. Stat. Ann. § 48:12-90.1

Every track motor car being operated on the rails of a railroad company, when such visability cannot be afforded by daylight, shall be equipped with an electric headlight either permanently attached or, if portable, in a fixed bracket, capable of illuminating the roadway ahead a distance sufficient to permit safe operation of the track motor car and also with a permanently attached or portable electrically energized red tail light to protect the track motor car from any following movement.